```

@api.multi 

 def button_export_pdf(self): 

 self.ensure_one()

 return self._export()

def _prepare_activity_statement(self): 

 self.ensure_one() 

 return 

{ 'date_start': self.date_start, 

 'date_end': self.date_end,

 'company_id': self.company_id.id,

 'partner_ids': self._context['active_ids'], 

 'show_aging_buckets': self.show_aging_buckets,

 'filter_non_due_partners': self.filter_partners_non_due,

 'account_type': self.account_type, }

def _export(self): 

 data = self._prepare_activity_statement()

 return self.env.ref( 'customer_activity_statement' '.action_print_customer_activity_statement').report_action( self, data=data)

```

Error is 
​

File "/home/usman/Documents/odoo12/odoo/odoo/addons/base/models/ir_actions_report.py", line 738, in _get_rendering_context
    data.update(report_model._get_report_values(docids, data=data))
AttributeError: 'report.customer_activity_statement.statement' object has no attribute '_get_report_values'

​